JP2007012969A - Laminated coil and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated coil used for a chalk coil, a transformer or the like for an electric circuit which is low-cost and high-quality, and also to provide its manufacturing method by which the manufacturing process is simplified and which is suitable for mass production. <P>SOLUTION: Each of flat and conductive sheet coils 2 is formed by a single turn or several turns and is provided with connections 8 near its ends. A film-like insulating material 10 is applied to each sheet coil 2 except its connections 8, and low melting metal 12 is allowed to adhere to the connections 8. At the time of lamination, insulating materials 10 are respectively interposed between stacked sheet coils 2, and the sheet coils 2 are piled so that their connections 8 may be opposed to one another. The whole lamination of the sheet coils 2 is heated and the low melting metal 12 adhering to the connections 8 is melted for electrically connecting the connections 8 of the sheet coils 2, and a spiral coil is formed in this way. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a laminated coil used for a choke coil or a transformer for an electric circuit, and a laminated coil.

  Conventionally, a coil for an electric circuit, for example, a choke coil, is an electric wire (a copper wire such as a magnet wire) with an insulation coating wound around a core material such as a silicon steel plate or a ferrite core at least once. When handling, use a wire with a thick wire wound around it.

  In addition, the current flowing through the coil is not a problem even when a general copper wire is wound when the frequency is several kHz or less, but when the current frequency is high, the current does not flow through the center of the conductor due to the skin effect. A phenomenon occurs. In order to avoid this skin effect, a thin copper wire that does not cause a skin effect is connected in parallel and wound, or a plate-like copper wire is wound instead of a round copper wire.

  For this reason, a coil using a printed circuit board has been developed to break away from the conventional winding. In order to connect such a printed circuit board coil to a coil of the next layer to be overlapped, a process such as making a hole in a base material which is an insulating layer and embedding a conductive pin for connecting to the hole is required. Become. For this reason, when forming a coil in multiple layers, there are processes such as forming inner vias as connection holes between layers sandwiching an insulating layer, and forming printed coils while avoiding unnecessary connection holes. is necessary.

  As another example, Patent Document 1 discloses a thin coil component and a manufacturing method thereof. As shown in FIG. 9, a plurality of insulating materials 54 having conductor coil patterns 52 and 53 provided on one side or both sides are laminated, and through holes 56 and pads for connecting the inner ends of the respective coil patterns. Through holes 60 are also provided in 58, and the inner walls of these through holes are plated to fix the conductors, thereby electrically connecting the inner ends to form a laminated coil. Japanese Patent Application Laid-Open No. H10-228561 describes an inductance element in which a large current is achieved by superimposing flat wires in the axial direction to form a spiral winding.

Japanese Patent Laid-Open No. 10-32129 JP 2003-17328 A

  However, the method of winding the above plate-like copper wire and winding the copper wire in parallel causes problems and costs such as winding processing, terminal processing, and pin binding processing, and uses a printed circuit board. However, there is a problem that the processing cost and material cost of the printed board are increased.

  In addition, the conventional printed circuit board coil has a problem in that it takes a lot of labor and costs such as the embedding of the pins or the processing related to the inner via, and prevents miniaturization. The laminated coil described in Patent Document 1 also requires a process of providing a through hole and fixing a conductor to the inner wall of the through hole by plating, and these labor and cost are problematic.

  The present invention has been made to solve the above-described problems, and provides a method for manufacturing a laminated coil and a laminated coil that can simplify the manufacturing process and are suitable for mass production, and are excellent in quality at low cost. For the purpose.

  In order to solve the above technical problems, the laminated coil manufacturing method according to the present invention is formed in one turn or a plurality of turns in a spiral shape as shown in FIG. Or a flat conductive sheet coil 2 provided with a connection portion 8 on one surface portion, and an insulating material 10 is applied in a film form on one or both surfaces of each sheet coil except for the connection portion 8 At the same time, the low melting point metal 12 is applied to the connecting portion 8 and the sheet coil 2 is wound when the connecting portions 8 of the overlapping sheet coils face each other and the connecting portions are made conductive. It is configured so that the directions are the same, and when stacking, the insulating material 10 is interposed between the overlapping sheet coils 2 and the sheet coils 2 are stacked so that the connection portions 8 face each other. Laminated sheetco Heating the entire Le, to melt the low melting point metal 12 attached to the connecting section, it is that the formation of the coil spirally electrically connecting the connecting portion 8 between the sheet coil. At this time, it is sufficient for the sheet coils at both ends of the layer of the laminated coil to have connection portions only on one surface portion.

  The method for manufacturing a laminated coil according to the present invention is such that a thermosetting adhesive 14 is interposed between the stacked sheet coils 2 and the sheet coils are bonded to each other by the heating.

  The method for manufacturing a laminated coil according to the present invention uses a 2 to 4 oxirane ring epoxy resin containing a 2 to 4 base acid anhydride as a curing agent as the insulating material 10.

  The manufacturing method of the laminated coil which concerns on this invention is using the epoxy resin of the 2 thru | or 4 oxirane ring which uses imidazole as the hardening | curing agent as the said insulating material 10. FIG.

  Moreover, the manufacturing method of the laminated coil which concerns on this invention is using the epoxy resin of the 2 thru | or 4 oxirane ring which uses a polyimide resin or a polyamidoimide resin as a hardening | curing agent as said insulating material.

  The manufacturing method of the laminated coil according to the present invention is that tin, lead, or solder is used as the low melting point metal 12.

  The method for manufacturing a laminated coil according to the present invention is that the sheet coil 2 is formed by punching a copper plate into a rectangular loop shape. Moreover, the manufacturing method of the laminated coil which concerns on this invention is coat | covering the mold material 20 which mixed the iron powder around the said sheet coil 2 laminated | stacked after the said heating.

  Moreover, the laminated coil which concerns on this invention is manufactured by the manufacturing method of one of the said laminated coils.

  According to the method for manufacturing a laminated coil according to the present invention, during lamination, an insulating material is interposed between the overlapping sheet coils, and the sheet coils are stacked and laminated so that the connection portions face each other. The whole is heated, the low melting point metal attached to the connection part is melted, and the connection parts of the sheet coil are electrically connected to each other to form a spiral coil. As a result, mass production can be easily performed, cost reduction can be achieved, and a large current capacity and high quality coil can be easily obtained.

  According to the method for manufacturing a laminated coil according to the present invention, since each sheet coil is bonded to each other by interposing a thermosetting adhesive between the stacked sheet coils, the sheet coils are bonded to each other well. There is an effect that the quality of the coil is improved.

  According to the method for manufacturing a laminated coil according to the present invention, since a 2 to 4 oxirane ring epoxy resin using a 2 to 4 base acid anhydride as a curing agent is used as an insulating material, a high glass transition temperature is ensured and low The temperature and melting point of the melting point metal are not changed even after cooling (for example, the coefficient of expansion is increased). The form and function of the insulating film between the sheet coils are maintained, and the thermal expansion is small. In addition, there is an effect that there is no adverse effect such as peeling.

  According to the method for manufacturing a laminated coil according to the present invention, since an epoxy resin having a 2 to 4 oxirane ring using imidazoles as a curing agent is used as an insulating material, a high glass transition temperature is secured as described above, and a low melting point metal is used. There is an effect that the material does not change even at the melting temperature, and the same effect can be obtained when a polyimide resin or a polyamideimide resin is used as a curing agent.

  According to the method of manufacturing a laminated coil according to the present invention, since tin, lead, or solder is used as the low melting point metal, the connection portions are electrically connected well and accurately by fusion connection of the low melting point metal and can withstand a large current. There is an effect that is.

  According to the method for manufacturing a laminated coil according to the present invention, since the sheet coil is formed by punching a copper plate into a rectangular loop shape, it is easy to manufacture, the cost can be reduced, and a coil having a large current capacity can be obtained. is there.

  According to the method for manufacturing a laminated coil according to the present invention, after heating, the laminated sheet coil is coated with a mold material mixed with iron powder, so that the magnetic flux is induced in the mold material and the magnetic field lines are efficiently tied. It is possible to increase the inductance of the coil.

  Since the laminated coil according to the present invention is manufactured by any one of the manufacturing methods described above, it can be manufactured by a consistent processing process, so that mass production can be easily performed and the cost can be reduced. Play.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a method for manufacturing a laminated coil and an embodiment of the laminated coil according to the present invention will be described with reference to the drawings. The laminated coil 1 is used as a coil such as a choke coil for an electric circuit. This laminated coil has a structure in which a single-turn sheet-like coil is laminated to form a multi-turn coil, and a multi-turn sheet-like coil is laminated to form a multi-turn coil. There is.

  As a first embodiment, an embodiment in which a coil is formed by stacking single-turn sheet-like coils will be described. FIG. 1 shows the one-turn sheet coil 2 for each layer, and the sheet coil 2 has forms from the first layer to the 15th layer. Each coil has an open loop shape in which the winding direction is rectangular and a predetermined gap 4 (gap) is formed in part.

  Of these sheet coils, a coil terminal portion 6 is formed at one end of each of the lowermost (first layer) and uppermost (15th) sheet coils so as to protrude from a rectangular frame, and the other end. Each is formed with a connection portion 8 electrically connected to another sheet coil. The sheet coils 2 from the second layer to the fourteenth layer have other surface portions near one end facing the gap 4 and other back surfaces near the other end. A connecting portion 8 connected to the sheet coil is formed.

  The sheet coil 2 is stacked, for example, sequentially from the bottom to the first layer, the second layer, and the third layer. At this time, the positions of the gaps 4 of the sheet coils 2 are formed so as to be sequentially shifted by one frame (a range of about the size of the connecting portion) in the same peripheral direction. Thereby, since the connection part 8 of the sheet coils 2 which overlaps up and down faces each other, if these are electrically connected and made conductive, a coil of 15 turns can be formed.

  Here, the manufacturing process and insulating material of the laminated coil 1 will be described. First, a sheet coil is manufactured by punching a conductive plate material by a punching process using a press. Here, the copper sheet is punched to produce the sheet coils 2 from the first layer to the fifteenth layer.

  Next, in the printing process, a resin composition material in which a curing agent and a catalyst are added to an epoxy resin as an insulating material 10 is applied to both surfaces (or one surface) of each sheet coil 2 to a predetermined thickness by a printing technique and heated. Curing to form an insulating film. At this time, it is necessary to remove the connecting portion 8 from the object of the insulating film. This is a method of applying the insulating material 10 by removing each connecting portion 8 at the time of application, or the entire sheet coil including the connecting portion 8. There is a method in which the insulating material 10 is applied to the connecting portion and the insulating film of the connecting portion is removed later by a mechanical or chemical method. In the form in which the insulating material 10 is applied to one side of each of the sheet coils 2, when the sheet coils 2 are stacked, the insulating material 10 is disposed on the surface of one of the facing sheet coils 2. To do.

  In this embodiment, an epoxy resin (bisphenol type epichlorohydrin resin) is used as the insulating material 10. This epoxy resin is excellent in heat resistance, electrical insulation, adhesive strength, and mechanical strength. An acid anhydride (methyltetrahydrophthalic anhydride) was used as a curing agent for this epoxy resin. Here, methyltetrahydrophthalic anhydride is liquid at room temperature, and is convenient for printing and has good workability.

  Through the in-house trial production of the laminated coil, the resin composition material using the above-mentioned bisphenol-type epichlorohydrin resin and the above-mentioned methyltetrahydrophthalic anhydride as the curing agent is particularly excellent in heat resistance because the glass transition temperature (Tg) is increased. It can be confirmed by a prototype that it is effective as the insulating material 10 and that the resin composition does not thermally change even at the temperature at which the following low melting point metal is melted, and the function as an insulating film is not impaired. It was. Moreover, imidazoles (2-ethyl-4-methylimidazole) were added to the resin composition as a catalyst.

  Generally, the following epoxy resins having a 2-oxirane ring to 4-oxirane ring system are excellent in heat resistance and can be used as the insulating material 10. Among these, as resins that can be used as the insulating material 10, the following resins have been confirmed by in-house tests and the like. Examples of the bioxirane ring epoxy resin include alicyclic epoxy resin, bisphenol type (A, F type, etc.)-Epichlorohydrin resin, bifunctional phenol type epoxy resin, and trioxirane ring type epoxy resin. There are phenol novolac resin, heterocyclic epoxy resin, and polyfunctional epoxy resin, and tetraoxirane ring type epoxy resin includes tetrafunctional phenol epoxy resin and tetrafunctional glycidylamine type epoxy resin. As the insulating material, thermosetting resin such as polyimide or polyamideimide, melamine resin and benzoguanamine resin are also confirmed to be good.

  Further, as a curing agent that contributes to heat resistance in combination with the epoxy resin, acid anhydrides of 2 to 4 bases are effective. Of these, materials and catalysts that have been confirmed by in-house tests and are effective as curing agents for the epoxy resin include the following. As the above two-base acid anhydride, methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc., tribasic acid anhydride, trimellitic acid, four-base acid anhydride, Examples include pyromellitic acid and 4,4′-oxydiphthalic anhydride. Other curing agents include 1-cyanoethyl-2-methylimidazole, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, isocyanuric acid addition salt, and the like It has been confirmed that imidazole-based curing agents, amine-based curing agents such as diaminodiphenyl ether, and 4,4-diaminodiphenylmethane are good. In addition, resins such as polyimide, polyamideimide, and melamine can be used as a curing agent, and it has been confirmed that excellent heat resistance characteristics are exhibited when used as a curing agent for the epoxy resin. As the catalyst, it has been confirmed that tertiary amines such as 2,4,6-tris (dimethylaminomethyl) phenol, or imidazoles are good for curing acceleration.

  An insulating material using the above-mentioned epoxy resin as a curing agent, such as the above-mentioned acid anhydride or the above-mentioned imidazole-based or amine-based curing agent, has an increased glass transition temperature and excellent heat resistance, and melts the following low melting point metals. The temperature does not change with heat, and the function as an insulating film is not impaired.

  After applying the insulating film, the insulating film made of the insulating material 10 on the surface of the connection portion 8 of each sheet coil 2 is removed by a technique such as etching. In this insulating film removing step, the insulating film on the surface of the connecting portion 8 is removed by a chemical method such as etching, a mechanical method, or a physical method such as laser beam, high-frequency dielectric heating, or discharge. Thereby, the electroconductive connection part 8 is each formed in the vicinity of each edge part of the surface part of the said sheet coil 2, and a back surface part.

  In the next plating step, the low melting point metal 12 is deposited (plated) on the conductive connection portion 8 of the sheet coil from which the insulating film has been removed. The low melting point metal 12 is preferably tin, lead, solder (tin-lead alloy), or the like. In particular, when the content of tin is high (60% or more), the solder has a low melting point, which is favorable. An alloy in which a small amount of nickel, silver, copper, or the like is mixed with tin can be used.

  At this time, as shown in FIG. 2, the thickness (M) of the low melting point metal 12 layer plated on the connection portion 8 of each sheet coil 2 is slightly thicker than the thickness (W) of the insulating film layer formed by the insulating material 10. Form to a degree (M> W). By making the thickness of the low melting point metal 12 layer thicker than the thickness of the insulating film layer of the insulating material 10, the low melting point metal 12 layers of the facing sheet coils are surely fused and conducted. Through the above-described consistent printing process and processing process, processing such as insulation for each sheet coil is completed.

  In the next laminating step, as shown in FIG. 3, the adhesive 14 is applied and applied to one or both sides of the sheet coil 2 with the connection portion 8 being left, and the sheet coils from the first layer to the 15th layer are laminated. Glue each other. As the adhesive 14, for example, a thermosetting adhesive such as an epoxy resin is used. For example, some of these adhesives melt at a low temperature (60 ° C. to 80 ° C.). When the above-mentioned lamination is performed in this state and the adhesive is exposed to a high temperature (120 ° C. or higher), a reaction occurs. Since it changes to a thermosetting adhesive, it adheres using this characteristic.

  In the last heating step, the laminated sheet coil is put in a heating furnace or the like and heated at a predetermined temperature. This heating temperature is a temperature in the vicinity of the melting point where the low melting point metal 12 melts. By this heating, the 12 low melting point metal 12 layers of the facing connection portions of the laminated sheet coil 2 are melted, and the connection portions facing each other are electrically connected and conducted by the low melting point metal. Moreover, the adhesive 14 is melted by the heating, and thereafter, the adhesive is thermally cured to bond the sheet coils.

  At this time, when a resin composition material obtained by applying the curing agent or the like to the epoxy resin is used as the insulating material 10, the insulating film made of the insulating material can withstand the melting temperature of the low melting point metal, and the insulating film itself It was confirmed that the insulation state was maintained well. Further, this insulating film did not react with the low melting point metal, and the low melting point metal did not flow out. Furthermore, since this insulating film has little thermal expansion, it does not affect the form of the laminated sheet coil by heat treatment and is good.

  After cooling, the adhesive 14 is cured to bond the sheet coils 2 together, and the connecting portions 8 of the overlapping sheet coils are electrically connected by the low melting point metal 12. Thereby, each sheet coil is helically connected, and the laminated coil 1 of 15 turns is formed as a whole. The periphery of the laminated coil 1 is further coated with an insulating film with an epoxy resin, an insulating tape or the like.

  Then, as shown in FIG. 4, a core material 18 made of a magnetic material, for example, an iron core, is inserted into the rectangular hollow portion of the laminated coil 1. As the core material, steel material, ferrite, cobalt, nickel or the like can be used. Next, a resin mold material 20 is coated around the laminated coil 1 and the core material 18 to a predetermined thickness. As this molding material 20, for example, an epoxy resin or the like mixed with iron powder and carbon powder is used. This iron powder induces a magnetic flux as a magnetic material, and can efficiently connect magnetic lines of force, thereby increasing the inductance of the coil. Further, the efficiency of cooling of the coil can be improved by the heat conduction effect of the iron powder and the carbon powder.

  Further, as shown in FIG. 5, in the resin mold, the bulging portion 22 is formed on the outer portion (on the opposite side in the center direction) of the laminated coil 1. Without this bulging portion, the thickness of the resin mold in the outer portion of the laminated coil 1 becomes narrow, and the magnetic lines of force go around in the atmosphere, which is not preferable. By providing the bulging portion 22, the passage of the magnetic force lines 23 is widened, and the magnetic flux is induced inside the molding material 20 and the molding material of the bulging portion 22, and the magnetic force lines are efficiently connected to increase the coil inductance. .

  The choke coil 16 using the laminated coil 1 is completed by the resin mold. As shown in FIG. 6, the choke coil 16 has a bottom surface portion in a state in which the coil terminal portion 6 of the first layer sheet coil and the coil terminal portion 6 of the 15th layer sheet coil protrude upward. Is fixed to the substrate using a fastening tool such as a self-tapping screw. This choke coil is particularly useful as a coil for a power factor correction circuit that handles a large current, such as an air conditioner for air conditioning. The laminated coil 1 can also be used as a transformer coil.

  Therefore, according to the laminated coil according to this embodiment, it is possible to manufacture by a consistent processing process such as a punching process, a printing process, a plating process, and a heating process. Therefore, mass production can be easily performed and cost can be reduced. . In addition, since there is no base material, there is no need for a drilling process, the production can be performed quickly, and the use of the copper plate and the multilayering are easy, so the effect of the skin effect can be reduced and several hundred A (amperes). Large current capacity coils can be easily made.

  In addition, the sheet coil from the 1st layer to the 15th layer shown in FIG. 1 is arranged on one copper plate, the insulating material 10 is applied to the entire copper plate, and then the insulating material corresponding to the connection portion 8 is removed. Alternatively, the insulating material 10 is applied while leaving the connection portions 8, and the low melting point metal 12 is plated on the connection portions 8. Then, each sheet coil is punched out by pressing, and thereafter, the lamination step and the overheating step are performed. Then, a laminated coil may be obtained.

  Furthermore, there is a method for obtaining a plurality of laminated coils simultaneously. In this method, a plurality of first-layer sheet coils are arranged on the first copper plate, and the insulating material 10 is applied and the low melting point metal 12 is plated on the entire copper plate as described above. Similarly, a plurality of second-layer sheet coils are arranged on the second copper plate so as to overlap with the first-layer sheet coils, respectively, and the insulating material 10 is applied thereto and the low melting point metal 12 is plated. Similarly, third to fifteenth layer sheet coils are formed on the third and subsequent copper plates. Then, the first to fifteenth copper plates are laminated by applying an adhesive in the same manner as in the above-described laminating process (or dividing them several times at a time) and then punching out all the sheet coils at once. A plurality of laminated coils are obtained. At this time, the burrs remaining in the punched portions are deleted.

  Next, in connection with the second embodiment, an embodiment will be described in which a multi-turn (here, 4-turn) sheet-like coil is laminated to form a multi-turn laminated coil. FIG. 7 shows the sheet coil 32 constituting this laminated coil for each layer. These sheet coils 32 are composed of six sheets from the first layer to the sixth layer, and each is a four-turn sheet coil. Each of the sheet coils 32 has a rectangular winding direction, a coil is formed in a spiral shape toward the inside (or outside) of the sheet, and both end portions are open.

  One end of each of the sheet coils 32 at the lowermost end (first layer) and the uppermost end (sixth layer) of the sheet coil 32 is formed with a coil terminal portion 36 in a state protruding from a rectangular frame, and the other end. Each part is formed with a connecting part 38 electrically connected to another sheet coil. The sheet coils 32 from the second layer to the fifth layer are connected to other sheet coils on the surface portion near the end on one end side and on the back surface near the end on the other end side, respectively. A connecting portion 38 is formed. Each sheet coil 32 is formed with a connecting portion 38 so that the connecting portions near one end overlap each other and the winding direction is the same when the connecting portions are made conductive.

  The sheet coil 32 is sequentially stacked, for example, from the bottom to the first layer, the second layer, and the third layer. At this time, the connecting portions of the sheet coils 32 that overlap in the vertical direction are arranged so as to face each other. If these are electrically connected and conducted, a coil of 24 turns (= 4 × 6) is obtained.

  The material used for the manufacturing process and insulation of the laminated coil of this form is basically the same as that of the laminated coil 1 described above. First, the sheet coils from the first layer to the sixth layer are manufactured by a punching process using a press. In this step, each sheet coil is made by punching a copper plate.

  As shown in FIG. 8, in the printing process, the insulating material 10 is printed to a predetermined thickness on both surfaces of each sheet coil to form an insulating film. After applying the insulating film, the insulating film made of an insulating material on the surface of the connection portion 38 of each sheet coil 32 is removed by a technique such as the etching process.

  Further, in the next plating step, the low melting point metal 12 is deposited by plating on the conductive connection portion 38 of the sheet coil from which the insulating film has been removed. Next, the adhesive 14 is applied to one or both sides of the sheet coil 32, leaving the connection portion 38, and the sheet coils from the first layer to the sixth layer are stacked and bonded together.

  Finally, the laminated sheet coil is put in a heating furnace or the like and heated at a predetermined temperature. By this heating, the low melting point metal of each facing connection portion of the laminated sheet coil is melted, and the facing connection portions are electrically connected to each other by the layer of the low melting point metal. Moreover, the adhesive 14 is melted by the heating, and thereafter, the adhesive is thermally cured to bond the sheet coils. After cooling, the adhesive is cured to bond the sheet coils, and the connecting portions of the overlapping sheet coils are electrically connected to each other with a low melting point metal, thereby forming a 24-turn laminated coil.

  Further, an insulating film is applied around the laminated coil with an epoxy resin, an insulating tape or the like. And the said core material which consists of magnetic materials is inserted in the rectangular-shaped hollow part of this laminated | stacked coil. Next, the mold material 20 is coated around the coil and the iron core to perform resin molding. Moreover, in the said resin mold, the bulging part is formed in the outer side (anti-center direction side) part of a coil. With this resin mold, a choke coil using a laminated coil is completed. This choke coil is also useful for a power factor correction circuit such as an air conditioner for air conditioning. The laminated coil can also be used as a transformer coil.

  Therefore, the laminated coil according to this embodiment can be manufactured by consistent processing steps such as a punching process, a printing process, a plating process, and a heating process, as in the case of the laminated coil, and mass production is thus easy. It can be done and the cost can be reduced. Further, the sheet coil constituting the laminated coil has a large surface area and can reduce the influence of the skin effect, and thus the current capacity can be increased.

It is a figure which concerns on embodiment of this invention and shows the sheet coil from the 1st layer which comprises a laminated coil to the 15th layer. FIG. 4 is a diagram (partial cross-sectional view taken along line AA in FIG. 1) showing the state where an insulating material is applied to the sheet coil and a low melting point metal is adhered to the sheet coil according to the embodiment. It is a figure which shows the state which apply | coats an adhesive agent to the sheet coil which concerns on embodiment, and adheres sheet coils. It is a figure which shows the state which gave the resin mold to the laminated coil which concerns on embodiment. It is a figure which shows the state which provided the bulging part in the resin mold given to the laminated coil which concerns on embodiment. It is a figure which shows the laminated coil which concerns on embodiment, (a) is a side view, (b) is a figure which shows a plane. It is a figure which concerns on other embodiment and shows the sheet coil from the 1st layer which comprises a laminated coil to the 6th layer. FIG. 9 is a view (partial cross-sectional view taken along line BB in FIG. 7) showing a state where an insulating material is applied to a sheet coil and a low-melting point metal or the like is adhered to another embodiment. It is a figure which shows the laminated coil which concerns on a prior art example.

Explanation of symbols

2 Sheet coil 8 Connection 10 Insulation material 12 Low melting point metal 14 Adhesive

Claims (9)

Using a flat conductive sheet coil that is formed into a single turn or a plurality of turns in a spiral shape, and has a front surface portion and a back surface portion in the vicinity of the end portion, or a connection portion provided on one surface portion,
On one or both sides of each sheet coil, an insulating material is applied in the form of a film except for the connection part, and a low melting point metal is applied to the connection part,
The sheet coil is configured so that the connecting portions of the overlapping sheet coils face each other and the winding direction is the same when the connecting portions are made conductive, and the sheets overlap when the layers are stacked. Each sheet coil is stacked so that the insulating material is interposed between the coils, and the connecting portions face each other,
The entire laminated sheet coil is heated, the low melting point metal adhering to the connecting part is melted, and the connecting parts of the sheet coil are electrically connected to form a coil in a spiral shape. A method for manufacturing a laminated coil.   The method for producing a laminated coil according to claim 1, wherein a thermosetting adhesive is interposed between the stacked sheet coils, and the sheet coils are bonded to each other by the heating.   3. The method for manufacturing a laminated coil according to claim 1, wherein an epoxy resin having 2 to 4 oxirane rings using a 2 to 4 base acid anhydride as a curing agent is used as the insulating material.   The method for producing a laminated coil according to claim 1 or 2, wherein an epoxy resin having 2 to 4 oxirane rings using imidazole as a curing agent is used as the insulating material.   The method for producing a laminated coil according to claim 1 or 2, wherein an epoxy resin having 2 to 4 oxirane rings using a polyimide resin or a polyamideimide resin as a curing agent is used as the insulating material.   6. The method for manufacturing a laminated coil according to claim 1, wherein tin, lead, or solder is used as the low melting point metal.   The method for manufacturing a laminated coil according to any one of claims 1 to 6, wherein the sheet coil is formed by punching a copper plate into a rectangular loop shape.   8. The method of manufacturing a laminated coil according to claim 7, wherein a mold material mixed with iron powder is coated around the laminated sheet coils after the heating.   A multilayer coil manufactured by the method for manufacturing a multilayer coil according to any one of claims 1 to 8.

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